ALBANY – The Ethics Commission issued a tough new policy on the use of state aircraft yesterday, requiring officials to fly primarily on government business and, if politics are involved, to reimburse the state at sky-high charter rates.

The action by the commission, controlled by Gov. Spitzer, comes as it also probes the dirty-tricks scandal involving the use of the State Police by top Spitzer aides. Trooper records were used to prove Senate Majority Leader Joseph Bruno (R-Rensselaer) was improperly using state aircraft for political purposes.

The ethics panel’s action changes a 12-year-old policy that allowed former Gov. Pataki and other officials to use the aircraft for both government business and political events without having to reimburse the state.

The commission noted that, as an executive branch agency, it does not possess the power to impose its new rules on Bruno or other members of the Legislature who fly on state aircraft.

But the commission said that since Spitzer’s office controls the State Police, which oversees executive aircraft, the governor does have the power to institute the new standards on all those wishing to fly, including legislators.

Some sources described the commission’s sudden action as an effort to give Spitzer and his top aides political cover as several investigations into the scandal continue.

“This allows the governor and his people to say, ‘See, we were really looking into a serious problem,’ ” said one source close to the probe.

Bruno spokesman John McArdle said, “The timing of this report is suspicious, given the fact that this commission is charged with investigating the governor and his aides.”

Meanwhile, Senate Republicans will give Spitzer’s inspector general an ultimatum as soon as today: Appear voluntarily at a hearing on the scandal or be subpoenaed to testify, sources said.

The sources said the Senate Investigations Committee would again “invite” Inspector General Kristine Hamann to appear at a committee hearing on the scandal, most likely in September.

“If she turns us down a second time, we are definitely prepared to issue a subpoena,” said a source close to the committee.

Hamann initially agreed to show up for last week’s hearing, then abruptly refused to attend.